Medical extractors have been used for the removal of various bodily tissue, including stones or calculi, or other foreign objects, from within the body. One type of extractor has a basket connected to the distal end of a wire. The extractor may also include a sheath that is moveable relative to the basket and the wire, and the basket may include a number of legs. The basket may be deployed as the sheath is withdrawn from the legs and may be collapsed as the sheath is extended over the legs. Once the basket is deployed, a targeted stone may be captured within the basket. The device may further include a proximal handle and a slide, connected to the sheath and wire, for deploying and collapsing the basket.
The effectiveness of a stone retrieval device may depend on the desired balance between basket flexibility and basket strength. Conventional baskets may include elements made solely of one material. Such elements may have the same strength, flexibility, or other mechanical characteristics throughout, making it difficult to achieve this balance. For example, basket legs made of steel may be relatively strong and rigid, but may be relatively inflexible as compared to legs made from other more pliable materials. On the other hand, basket legs made of nitinol may be relatively more flexible, but exhibit less strength. Thus, baskets or other parts of a medical retrieval device made from elements composed of a single material may suffer from the mechanical disadvantages of the material used to form the elements.
The present disclosure provides medical retrieval devices that avoid some of the aforementioned shortcomings of existing devices.